Extracellular polymeric substances altered ferrihydrite (trans)formation and induced arsenic mobilization

Gao，Kun1; Wang，Shuai1; Zhou，Wenjing1; Zhang，Bowei1; Dang，Zhi2; Liu，Chongxuan1

2024-07-15

10.1016/j.jhazmat.2024.134434

Journal of Hazardous Materials   影响因子和分区

0304-3894

1873-3336

The behavior of As is closely related to trans(formation) of ferrihydrite, which often coprecipitates with extracellular polymeric substances (EPS), forming EPS-mineral aggregates in natural environments. While the effect of EPS on ferrihydrite properity, mineralogy reductive transformation, and associated As fate in sulfate-reducing bacteria (SRB)-rich environments remains unclear. In this research, ferrihydrite-EPS aggregates were synthesized and batch experiments combined with spectroscopic, microscopic, and geochemical analyses were conducted to address these knowledge gaps. Results indicated that EPS blocked micropores in ferrihydrite, and altered mineral surface area and susceptibility. Although EPS enhanced Fe(III) reduction, it retarded ferrihydrite transformation to magnetite by inhibiting Fe atom exchange in systems with low SO. As a result, 16% of the ferrihydrite was converted into magnetite in the Fh-0.3 treatment, and no ferrihydrite transformation occurred in the Fh-EPS-0.3 treatment. In systems with high SO, however, EPS promoted mackinawite formation and increased As mobilization into the solution. Additionally, the coprecipitated EPS facilitated As(V) reduction to more mobilized As(III) and decreased conversion of As into the residual phase, enhancing the potential risk of As contamination. These findings advance our understanding on biogeochemistry of elements Fe, S, and As and are helpful for accurate prediction of As behavior.

Arsenic Biogeochemistry Extracellular polymeric substances Ferrihydrite Sulfate-reducing bacteria

SCI ; EI

英语

第一 ; 通讯

20242116114898

Aggregates ; Bacteria ; Magnetite ; Organic compounds ; Sulfur compounds

Highway Engineering:406 ; Concrete Reinforcements:412.2 ; Geochemistry:481.2 ; Biochemistry:801.2 ; Organic Compounds:804.1

ENGINEERING

2-s2.0-85193430505

Scopus

1.State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China
2.The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters,Ministry of Education,South China University of Technology,Guangzhou,510006,China

Gao，Kun,Wang，Shuai,Zhou，Wenjing,et al. Extracellular polymeric substances altered ferrihydrite (trans)formation and induced arsenic mobilization[J]. Journal of Hazardous Materials,2024,473.

Gao，Kun,Wang，Shuai,Zhou，Wenjing,Zhang，Bowei,Dang，Zhi,&Liu，Chongxuan.(2024).Extracellular polymeric substances altered ferrihydrite (trans)formation and induced arsenic mobilization.Journal of Hazardous Materials,473.

Gao，Kun,et al."Extracellular polymeric substances altered ferrihydrite (trans)formation and induced arsenic mobilization".Journal of Hazardous Materials 473(2024).